The E-style external retaining ring has a tapered section, assembles radially, is made of alloy 25 copper with a plain finish, and is made in USA. The ring's E-style shape has three points of contact with the shaft for retention when installed. The tapered section style provides the ring with flexibility to facilitate installation and typically withstands higher thrust loads than constant section and spiral rings. The ring installs by sliding it onto a shaft from the side, also called radial assembly. Often used when the shaft end is not reachable, radial assembly rings enable quicker installation than axially installed rings but may require deeper grooves. Alloy 25 copper is a nonmagnetic, corrosion-resistant metal that is electrically and thermally conductive.

Retaining rings attach to a shaft (external) or install in a bore (internal), creating a shoulder to maintain component positioning within an assembly. While most rings install into a machined groove either on the inside or outside diameter of a shaft, self-locking rings attach to a shaft by using friction from means such as teeth and notches to maintain placement. Retaining rings should fit tightly enough into the groove or onto the shaft so they won't experience any movement.